DESCRIPTION: The objective is to investigate analysis of saliva in screening for elevated total cholesterol and LDL- cholesterol in individuals at risk of cardiovascular disease and in the general adult population. Saliva is proposed as a non-invasiv'e substitute for blood testing. Evidence is presented that total salivary cholesterol corresponds with serum cholesterol. Apolipoprotein B, the protein component of LDL-cholesterol, is also shown to exist in saliva in which it can be detected by a sensitive immunoassay. Saliva ApoB can be used to estimate the concentration of the serum LDL from which it is derived. The specific aims of Phase I are: (1) establish a quantitative enzyme assay for total cholesterol ini saliva; (2) define the quantitiative distribution of cholesterol in three fractions of saliva (free, amount bound to soluble proteins, amount bound to insoluble mucins); (3) validate quantitative precision of ApoB immunoassay in saliva matrix; (4) determine by electrophoretic immunoblotting the molecular species in saliva cross-reacting with and ApoB and their relationship to parent LDL; (5) investigate daily variation in distribution and secretion of saliva cholesterol and ApoB and impact of meals; (6) conduct a small clinical study in which saliva cholesterol and ApoB are compared to blood cholesterol, ApoB, LDL and HDL in a patient population showing specific types of diagnosed hypercholesterolernic states. Best methods of sample preparation for assay of cholesterol and ApoB will be incorporated into a prototype saliva collection device to be fabricated and tested in a clinical trial in Phase II.